The present invention relates to a fastener that may be pre-assembled with a panel to ease the installation of said panel. More specifically, the present invention relates to a fastener that may be pre-assembled with a panel wherein the fastener is in a recessed position prior to installation of the panel.
When assembling a thin, sheet-like part to a thin-walled substructure, such as where a rocker panel is secured to the frame of an automobile, it is common to use single-piece, injection molded plastic fasteners to inexpensively and quickly secure the panel to the metallic support structure. A typical, prior art plastic fastener used in this application is not unlike a typical machine screw, having an upper flange or head from which extends a shaft. However, the shaft of such a prior art fastener typically has a retaining structure that engages a bore formed through the substructure into which the fastener is driven.
Preferably, a typical prior art plastic fastener will be constructed and arranged to be driven into a bore formed in the substructure at relatively low pressures such that special tools are not required to install the fastener. Prior art fasteners may be passed entirely through the part that is to be secured to the substructure or may form a xe2x80x9cblindxe2x80x9d connection wherein the head or flange of the fastener is inserted and retained in a structure, sometimes known as a dog house, which extends from the undersurface of the plastic part. In any case, because the parts with which typical prior art fasteners are used are often fabricated at locations remote from where the parts are assembled with, their substructures, it is preferred to pre-assemble the fasteners with the part with which they are used. Where this is the case, the part may simply be removed from the container in which it was shipped, positioned appropriately with regard to the substructure, and installed by inserting the shafts of the pre-assembled prior art fasteners into appropriate bores formed through the substructure such that the retaining structures on the shaft of the fasteners can retain the fasteners in the bore in the substructure.
Problems arise however where a relatively rigid part, such as the aforementioned rocker panel, require the use of a plurality of fasteners that are misaligned with one another. In such a case, it may be possible to properly install one or more fasteners or groups of fasteners that are aligned with one another, i.e., the axes along which the shafts of the fasteners extend being substantially parallel with one another, but difficult to install other, distinct fasteners or groups of fasteners that are not directly aligned with those fasteners or groups of fasteners that were first installed. In these instances, pre-assembly of the fasteners with the part may be contraindicated as assembly of the part with its substructure may be difficult or impossible without damage to one or more fasteners or even the part itself. In these cases it is desirable to utilize specially adapted fasteners that facilitate pre-assembly of the part with its requisite fasteners.
The present invention comprises a fastener for securing a panel to a substructure. This fastener has a body and a head that are resiliently connected to one another to allow for relative movement. The body of the fastener comprises a pair of offset flanges that are connected to one another by a hollow support structure having a bore formed longitudinally therethrough in generally perpendicular relation to the pair of offset flanges. One alternate embodiment of the present invention may include an open channel support structure rather than the hollow support structure. This alternate embodiment is open at one side whereas the hollow support structure is tubular and therefore closed.
The head of the fastener comprises an additional flange from which extends a shaft. This shaft extends generally perpendicular from the flange of the head and has formed therein a retaining mechanism that is constructed and arranged to securely retain the shaft of the fastener within a bore formed in the substructure when the head of the fastener is moved from a first, pre-assembled position to a second, fully assembled position.
The body of the fastener may also comprise one or more retention tabs or members that extend into the space between the offset flanges of the head. These retention tabs are constructed and arranged to engage complementary bores, slots, or depressions formed in the panel structure so as to maintain the fastener in a predetermined location with respect to the panel structure.
The retaining mechanism that extends from the shaft of the fastener may comprise one or more detents, flexible fingers, or frustoconical flexible extensions that extend laterally and toward the additional or third flange of the head of the fastener.
It is to be understood that the fastener of the present invention is well adapted for pre-assembly with a panel by inserting the support structure, open or tubular, a slot formed in a panel structure. When pre-assembled with the panel, the pair of offset flanges of the body of the fastener are positioned on opposing sides of the panel structure. The fastener may be aligned with other fasteners pre-assembled with the panel or may be pre-assembled with one more of the fasteners out of alignment with the remaining fasteners. The pre-assembly of the fastener with a panel and the subsequent assembly of the panel with its substructure are facilitated by the fact that the tip of the shaft of the head of the fastener may be substantially withdrawn into the support structure when the head of the fastener is in a first, pre-assembled position.
The fastener of the present invention lends itself for use in a method of assembling a panel structure to a substructure. In this method a fastener of the type described hereinabove and comprising a body having a pair of offset flanges connected in a generally parallel relationship to one another by a support structure, the support structure having a bore formed longitudinally therethrough, a head having an additional or third flange from which extends in the direction of the body a shaft having at least one retaining mechanism extending laterally therefrom, the shaft extending at least partially into the bore formed through the hollow support structure, the body and the head of the fastener being interconnected by at least one flexible member, a tip of the shaft of the fastener being substantially withdrawn into the hollow support structure, is provided. This fastener is then pre-assembled with the panel structure such that the support structure of the body of the fastener is inserted into a slot formed into the panel structure in a predetermined position with regard to the panel structure. The panel, now pre-assembled with at least one fastener is next aligned with a substructure such that the fastener is aligned with a bore formed through the substructure. Finally, a force is applied to the head of the fastener so as to insert the shaft of the fastener into the bore formed through the substructure such that the retaining mechanism of the fastener engages the substructure and secures the panel structure to the substructure. Note that the body of the fastener may or may not include one or more retaining members or tabs that are constructed and arranged to engage a bore formed in the panel structure so as to align the fastener in a predetermined position with regard to the panel structure.
One area where this method is particularly useful is in the assembly of a rocker panel of an automobile to the frame of the automobile.